Field of the Invention
The invention relates to a hot air hand welding device with a plastic housing that forms a bar-like grip element that is provided with air inlet openings and in which a commutator motor is secured for driving a blower wheel that is surrounded by a larger diameter section of the housing adjacent to the grip portion and with an end section adjoining this larger diameter section opposite the grip portion which has a connecting device for a heating cartridge and a protection and connection tube that surrounds this heating cartridge.
Because the outside diameter of the grip portion may not exceed a given value in order to assure convenience in handling the device, and because in known devices of the above-described type, the commutator of the motor housed in the grip portion is arranged on the side of the rotor facing the free end of the grip portion, a space for housing the carbon brushes that cooperate with the commutator is limited. In the known device, therefore, the carbon brushes have a relatively short effective life. Also, disadvantageous is the fact that the mounting of the commutator motor is relatively expensive as is the mounting of the elements connected with it in the grip portion of the housing. If an air quantity control is provided, it is accomplished by changing the size of the openings in the air inlet provided in the grip portion. The result, therefore, can be excessive temperatures in the motor and, above all, in the control electronics for the heating cartridge, which is arranged between the commutator motor and the free grip end in the air flow that enters there. Additional disadvantages in the known devices are seen in the fact that nozzles can be provided either of the push-on type or screw-on type and that the hand of the servicing person is in danger of coming into contact with the protection and connection tube, which, during operation, may have an extremely high temperature. This danger is present particularly when the end device supporting the nozzle must be pressed against the welding point.